Inside pipe cutter



J1me 1944- v v. D. DAVIDSON ET AL I 2, 9

I INSIDE PIPE CUTTER VERNDIVDEE 014 I406 N MIL 0 C. v WILSON INVENTOR.

Patented June 20, 1944 UNITED PArsNr OFFICE INSIDE PIPE CUTTER,

Vernon Dee Davidson and Milo C. Wilson,

Corpus Christi, Tex.

Application October 5, 1942, Serial:No. 460,744

2 Claims. Cl. 1s4 0.7) i

This invention relates to pipe cutters, and more particularly to adevice which may be lowered into a Well for severing a pipe therein sothat the severed section of the pipe may be removed from within thewell.

It is an object of the invention to provide a pipe cutting device havingan anchor assembly and a cutter-assembly of which the latter isreleasable from the former at a desired level in the well and maythereafter be lowered to secure the device in operating position at thatlevel.

Another object is to provide'a device of the class described in whichthe assemblies may be intereng aged by lifting of the cutter assemblyrelative to the anchor assembly and may there after be released byrotation of the former relative to the latter.

Another object is to provide .a resilient split ring connection betweenthe anchor and cutter assemblies. I

A further object is to provide-a novel swivel connection between therotatable'and stationary elementsof the device.

Still another object 'is to provide a device which is simple inconstruction and which is so constructed that difiiculty from debrisfrom within the'well is minimized. 1

Still another object is to provide a device which is of ruggedconstruction so thatnumerous cuts -may be made without repair orreplacement of tion with the accompanying drawing in which:

Fig. 1 is an elevational view in section showing one embodiment of theinvention, the parts thereof being shown in relative position while thedevice is being lowered within a Well;

Fig. 2 is a sectional view similar to that shown in Fig. 1, but showingthe device within a pipe whichhas been cut thereby;

Fig. 3 is an elevational View of the device, the upper end beingshown insection to show the manner of connecting the device to an operatingstring;

Figs. 4, 5 and 6 are sectional views taken respectively upon lines 4-4,55 and 6-'6 in Fig. 1.

In the drawing the numeral I refers to a composite cutter assembly whichincludes an expander 2 'swivelly connected thereto and adapted to movewithin an anchor assembly 3 so that such anchor assembly may be securedat a desired position within a pipe to be cut and the locus of thecutting action is thereby determined.

r The cutter assembly I includes a body member 4 having a head 5 and amandrel 6 integral there'- with and of a reduced cross section. Themandrel is threaded at 1 at'its lower end and has a collar 8 fixedthereon, such collar having external threads l2 thereon. A guide member9 is attached to the 'm'an'drel below the collar 8. The body member 4and the guide member 9 have coaxial bores l and II so" that flushingfluid may be pumped downwardly through the tool during cuttingoperations.

The head is slotted at [5 and a cutter blade I6 is mount'ed ineach ofthe slots upon a pivot l'l. Each of the blades l6 has an upwardextension or ear H! to which pressure is applied by means of acompression spring l9 so that the bit at the lower end of each blade isnormally retracted inwardly to a position within the peripheral outlineof the tool.

Attentionnis directed to the fact that the shoulder between the head 5and the mandrel 6 is curvilinear.

angular cut in the manufacture of the device, and for this reason theresulting structure is more resistant to torsional and bending stressesat this point to which the device is subjected while in use.

As will more fully appear, the expander 2 is movable axially of themandrel 6 and in order to limit the upward travel of the expander andassociated elements, additional slots 26 are provided in the 'head 5intermediate the cutter blades 16. In'each of the slots 26 is positioneda stop member 21 which is secured in place by means of a pin 28.

The mandrel 6 is also reduced at 30 to receive an inwardly extendingannular flange 3| on sectors 32 which are assembled about the'mandreland held in assembled relation by means of the Wedge ring 33. This wedgering is threaded internally at its lower end to engage the threadedupper end 34 of the sectors 32.

The wedge ring 33 has upwardly extending fingers 35 extending into theslots I5 and having tapered surfaces 31'engageable with the lowertapered and arcuate'surfaceof the cutter blades l6. The fingers 35therefore rotate with the body member 4 and serve to force the bits 2|]outwardly to cutting position in a manner that will presently'appear. a

As previously explained, the expander 2 is slidably mountedtupon themandrel B and is pro-i vided with a recess 40 at its upper end toreceive the inwardly extending flange 4| on the sectors This is animportant feature of the invention since there iseliminated any sharp ofthe slip member 46 which has upwardly extending fingers 4.1 providedwith outer;serrations 48 for engagement with a surrounding tubing to becut. Such engagement is brought about by relative axial movement betweenthe slip as-' stop ring 58.

upon the pressure applied downwardly upon the cutter assembly I. Forthis reason any desirable cutting action may be brought about bycontrolling the weight applied upon the cutter assembly and the rate ofrotation thereof.

When the device of the invention is to be withdrawn from the well ormoved to a different position for a successive cut, the operating string55 is lifted together with the cutter assembly I.

-' Such lifting causes the collar 8 to enter the split ring 53 which islimited in upward travel by the The lifting force then causes the ring53 to expand so that an interconnection is sembly 3 and the expander 2in such a manner that the fingers 41 are forced outwardly by theexpander.

A sleeve member 50 is attached to the lower end of the slip member 46and terminates ineteriorly at its lower end in a downwardly taperedsurface 52 with which wedging action may be produced upon a split ring53 which-has a complementary exterior surface and, which is threadedinternally for engagement with the threads I2 upon the collar 8. Thesplit, ring 53: is held against. rotation by means of a pin 54 in thewall of the. sleeve 50-. i

The stiffness of the ring 5.3 andits initial. dimensions cause theringto inherently grip the threads on the periphery of the collar 8. Forthis reason this feature of construction is of importance in that itinsures uniform interengagement of the threads whereby a connectionbetween the cutter assembly land the slip assembly 3 is assured.

In the operation of the device above described as an embodiment of theinventiomzthe respective elements are initially in the relativepositions shown in Figs. 1 and 3, it being understood that the device isattached to an operating string 55 by means of the pin and boxconnection 56 (Fig. 3). The'bore ID in thedevice is a continuation ofthe bore in the-string 55 and it is to be understood that fluid can bepumped therethrough at any time during'the lowering and operation of thetool within a pipe to be out.

When the device has been lowered toa level where the surrounding pipe 51(Fig. 2) is to be cut, righthand rotation of the operating string willcause relative rotation between the cutter assembly I and the slipassembly 3. This is due to the fact that there is sufllcient frictionalengagement between the slip or anchor assembly 3 and the surroundingpipe or casing 51 to prevent rotation of the slip assembly within thepipe. Such rotation will cause unthreading of the connection between thesplit ring 53 and the collar 8 whereby the operating string and thecutter assembly I will be lowered relative to the anchor assembly 3.When the threaded connection between these parts has been released theentire operating string and cutter assembly can then be lowered,whereupon the expander 2 urges the slip fingers 41 outwardly into fixedengagement with the pipe or casing to be cut.

When the expander 2' has become wedged between the fingers 41, furtherdownward movement of the operating string 55 and the cutter assembly Iwill cause the cutter blades IE to ride upon the fingers 35 of the wedgering 33 whereby the bits or blades 20 will be forced outwardly intoengagement with the surrounding pipe. It seems apparent that the forcewithwhich the bits 20 are fed outwardly will depend entirely effectedbetween the cutter assembly I and the anchor assembly 3. Attention is'directed to the fact that this interconnection is completed withoutrelative rotation of the parts.

The parts. of the device are then in the relative positions shown inFig. 1 as above assumed preliminary to lowering the device into a well.Accordinglmthe, device may be raised or lowered within the, well, andadditional cuts may be made by a repetition of the operations justindicated.

While the invention has been disclosed by a description of the specificembodiment thereof, it is to be, understood that the invention is notconfined, to such specific, embodiment.

Broadly, the invention comprehends a pipe cutting device which may belowered into a well and operated to sever a pipe by rotation of oneportion of the device relative to another.

What is. claimed is:

1. In a pipe cutter the combination of, a body including a head and adownwardly extending mandrel, there being vertical slots in, said head,cutters pivotally mounted in said slots. and having outwardly directedcutter blades at their lower ends, an expander slidably surrounding themandrel, a reduced section in said mandrel, a

wedge ring on said expander having a portion entering said reducedsection so as to support said expander in retracted position, a. swivelconnection between said expander and wedge ring, said wedge ringincluding upwardly extending fingers to move within said slots and movethe cutters outwardly, and slip jaws movable relatively to the expanderto anchor the cutter assembly within a pipe to be cut.

2. In a pipe cutter the combination of a body including a head and adownwardly extending mandrel, there being vertical slots in said head,cutters pivotally mounted in said slots and having outwardly directedcutter blades at their lower ends, an expander slidably surrounding saidmandrel, a reduced section on the mandrel, said expander including aplurality of sectors surrounding said mandrel and having portionsentering said reduced section to support said expander on said mandrel,a swivel connection within the expander for said sectors, the upper endof said sectors forming a threaded area, a wedge ring threadablyengaging the threaded area to hold the sectors in position about themandrel, said wedge ring having upwardly extending fingers to enter saidslots and move the fingers outwardly, and slip jaws engageable by saidexpander and movable outwardly to hold the cutter in a fixed positionwithin the pipe to be cut.

VERNON DEE DAVIDSON. MILO. 0. WILSON.

